Antirust agent

ABSTRACT

The present invention provides a corrosion inhibitor for preventing rusting of metallic members during long-term storage thereof while maintaining cleanness of surfaces of the metallic members, as well as a corrosion inhibiting method. 
     The invention provides a corrosion inhibitor containing a hydroxylamine compound represented by formula (1): 
     
       
         
         
             
             
         
       
     
     (wherein each of R 1 , R 2 , and R 3  represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of these groups may have a substituent), or a hydrazine compound represented by formula (2): 
     
       
         
         
             
             
         
       
     
     (wherein each of R 1 , R 2 , R 3 , and R 4  represents a hydrogen atom, a C1 to C6 alkyl group, or a C2 to C4 alkenyl group, and each of these groups may have a substituent) and a water-absorbable resin; the corrosion inhibitor wrapped in a gas-permeable material; and a method of inhibiting corrosion characterized by including maintaining a metallic member in a gas barrier container in the presence of the wrapped corrosion inhibitor.

TECHNICAL FIELD

The present invention relates to a corrosion inhibitor which exhibits anexcellent corrosion inhibitory effect on a metallic material duringstorage thereof, and to a method of inhibiting corrosion.

BACKGROUND ART

Hitherto, there have been employed methods for preventing rust ofmetallic members caused by condensation of water vapor during storagethereof; e.g., an approach in which a metallic member is wrapped with adesiccant in a sealable material, an approach in which an object iswrapped in wrapping paper impregnated with a volatile corrosioninhibitor, and an approach in which an object is wrapped in a wrappingresin (film) containing a volatile corrosion inhibitor (see PatentDocument 1). In an alternative approach, a storage container formetallic members is purged with inert gas. When the approach using adesiccant is employed, rusting cannot be prevented even under completelydry conditions, and further rusting is caused by oxygen and water whichhave permeated the wrapping material with elapse of time.

The conventional approach in which an object is wrapped in wrappingpaper impregnated with a volatile corrosion inhibitor such asdicyclohexylammonium nitrite cannot be applied to storage of precisionparts or similar parts, since a long period of time is required forfully attaining corrosion inhibitory effect through vaporization of thecorrosion inhibitor, and the corrosion inhibitor component is depositedon a surface of a metallic member, thereby considerably deterioratingcleanness of the surface of the metallic member. The approach in whichan object is wrapped in a wrapping resin (film) containing a volatilecorrosion inhibitor attains unsatisfactory corrosion inhibitory effectduring wrapping of the object, since the volatile corrosion inhibitor islost through vaporization during production of the wrapping resin, andthe volatile corrosion inhibitor which has been incorporated into theresin is difficult to vaporize.

The approach in which a storage container is purged with an inert gassuch as nitrogen or argon encounters difficulty in complete removal ofoxygen contained in the storage container. Even when the container iscompletely purged with inert gas, oxygen and water present outside thecontainer material permeate the container with elapse of time, therebycausing rust. Thus, as mentioned above, when conventional approaches areemployed, rusting of metallic members during storage thereof for a longperiod of time cannot be prevented simultaneously with maintainingsurfaces of the metallic members clean. This raises a keen demand forsolving the drawbacks.

[Patent Document 1]

Japanese Patent Application Laid-Open (kokai) No. 2003-213462

DISCLOSURE OF THE INVENTION

The present invention provides a corrosion inhibitor for preventingrusting of metallic members during long-term storage thereof whilemaintaining cleanness of surfaces of the metallic members, as well as acorrosion inhibiting method.

The present inventor has found that, when a metallic member ishermetically maintained in a gas barrier container where a corrosioninhibitor package product containing a hydroxylamine or hydrazinecompound serving as an essential component and a water-absorbable resinretaining the compound is present, rusting of the metallic member can beprevented with maintaining cleanness of a surface of the metallicmember. The present invention has been accomplished on the basis of thisfinding.

Accordingly, the present invention is directed to the following.

1. A corrosion inhibitor comprising a hydroxylamine compound representedby formula (1):

(wherein each of R¹, R², and R³ represents a hydrogen atom, a C1 to C6alkyl group, or a C2 to C4 alkenyl group, and each of these groups mayhave a substituent), or a hydrazine compound represented by formula (2):

(wherein each of R¹, R², R³, and R⁴ represents a hydrogen atom, a C1 toC6 alkyl group, or a C2 to C4 alkenyl group, and each of each of thesegroups may have a substituent) and a water-absorbable resin.

2. A package product comprising the corrosion inhibitor as recited in 1above and a gas-permeable material which wraps the corrosion inhibitor.

3. A method of inhibiting corrosion, comprising maintaining a metallicmember in a gas barrier container in the presence of the package productas recited in 2 above.

The metal corrosion inhibitor of the present invention exhibits anexcellent inhibitory effect on rusting of a metallic material caused bycondensation of water vapor during storage thereof, and is able tomaintain cleanness of surfaces of metallic members. Therefore, when thecorrosion inhibitor is employed, a washing step (including rust removaland or cleaning metal surfaces), which would otherwise be required inmetal processing (plating, painting, etc.) after storage of the metallicmembers, can be eliminated, whereby processing time and cost forchemical liquids can be reduced.

BEST MODES FOR CARRYING OUT THE INVENTION

The metal corrosion inhibitor of the present invention is generallyapplied to iron. However, the corrosion inhibitor is also applicable toother metal species such as copper, nickel, chromium, cobalt, lead,zinc, aluminum, titanium, tin, gold, silver and alloys thereof. Thesemetallic species may be ground/cut products, die-cast molds, sinteredproducts, etc. The corrosion inhibitor may be applied to metallizedproducts made of a material such as resin, glass, or ceramic material,whose surfaces are metallized through adhesion, pressing, plating, vapordeposition, ion-plating, or similar means.

Specific examples of preferred hydroxylamine compounds represented byformula (1) include hydroxylamine, O-methylhydroxylamine,O-ethylhydroxylamine, N-methylhydroxylamine, N,N-dimethylhydroxylamine,N,O-dimethylhydroxylamine, N-ethylhydroxylamine,N,N-diethylhydroxylamine, N,O-diethylhydroxylamine,O,N,N-trimethylhydroxylamine, N-(2-methoxyethyl)hydroxylamine,N-allylhydroxylamine, N,O-diallylhydroxylamine, andO-cyclohexyl-N,N-dimethylhydroxylamine. Of these, hydroxylamine andN,N-diethylhydroxylamine are most preferred.

Specific examples of hydrazine compounds represented by formula (2)include hydrazine, methylhydrazine, ethylhydrazine,1,1-dimethylhydrazine, 1,2-dimethylhydrazine, 1,1-diethylhydrazine,1,2-diethylhydrazine, isopropylhydrazine, 1,2-diisopropylhydrazine,cyclohexylhydrazine, and allylhydrazine. Of these, hydrazine,methylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine,ethylhydrazine, 1,1-diethylhydrazine, and 1,2-diethylhydrazine are mostpreferred.

The corrosion inhibitor of the present invention preferably has ahydroxylamine compound concentration or a hydrazine compoundconcentration of 0.001 to 50 wt. %, more preferably 0.05 to 30 wt. %,particularly preferably 0.5 to 30 wt. %. When the concentration is lessthan 0.001 wt. %, the corrosion inhibitory effect is unsatisfactory,whereas when the concentration is in excess of 50 wt. %, the effect doesnot improve any further, therefore inappropriate for economical reasons.

In the present invention, when an immediate corrosion inhibitory effectis demanded, the composition containing the aforementioned hydroxylaminecompound or hydrazine compound and an additional acetylene alcohol ispreferably absorbed in water-absorbable resin. Examples of preferredacetylene alcohols include C3 to C10 acetylene alcohols such as1-propyn-3-ol, 1-butyn-3-ol, 1-butyn-4-ol, 2-butyn-1-ol,3-methyl-1-butyn-3-ol, 3-methyl-1-butyn-4-ol, 1-pentyn-3-ol,3-methyl-1-pentyn-3-ol, 1-hexyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol,1-ethynylcyclohexanol, 1-heptyn-3-ol, 1-octyn-3-ol, 1-nonyn-3-ol,1-decyn-3-ol, 2-butyn-1,4-diol, 3-hexyn-2,5-diol,3,5-dimethyl-3-hexyn-2,5-diol, and 4-ethyl-1-octyn-3-ol. Of these,3-methyl-1-pentyn-3-ol (methylpentynol), 3-methyl-1-butyn-3-ol(methylbutynol), 3,5-dimethyl-1-hexyn-3-ol (dimethylhexynol),1-ethynylcyclohexanol, etc. are most preferred. The corrosion inhibitorof the present invention preferably has an acetylene alcoholconcentration of 0.001 to 50 wt. %, more preferably 0.01 to 10 wt. %,particularly preferably 0.1 to 10 wt. %. When the acetylene alcoholconcentration is less than 0.001 wt. %, the corrosion inhibitory effectis unsatisfactory, whereas when the concentration is in excess of 50 wt.%, the effect does not improve any further, therefore inappropriate foreconomical reasons.

The water-absorbable resin of the present invention is formed of aswellable polymer which has a crystalline or cross-linked structure,which allows rapid absorption of water when in contact with water.Examples of such polymers include polyvinyl alcohol, poly(meth)acrylatesalts, poly(meth)acrylamide, polysulfonate salts, polyethylene oxide,carboxymethyl cellulose, acrylate salt-acrylate ester copolymers, vinylacetate-acrylate ester copolymers, and starch-acrylic acid graftcopolymer hydrolyzates. Preferably, the water-absorbable resin is ahardened resin obtained through reaction essentially between ahydrophilic epoxy resin (a) having two or more epoxy groups in amolecule thereof and an amine compound (b) having two or more primary orsecondary amine groups in a molecule thereof.

No particular limitation is imposed on the species of the aforementionedepoxy resin (a), so long as the epoxy resin is a hydrophilic compoundhaving two or more epoxy groups in a molecule thereof. Specific examplesinclude polyether-type epoxy resins obtained through reaction betweenepichlorohydrin and a glycol such as ethylene glycol, diethylene glycol,polyethylene glycol, propylene glycol, dipropylene glycol, orpolypropylene glycol; and polyhydric alcohol-type epoxy resins obtainedthrough reaction between epichlorohydrin and a polyhydric alcohol suchas glycerin, polyglycerol, trimethylolpropane, or sorbitol. Of these,polyethylene glycol diglycidyl ether, polypropylene glycol diglycidylether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, anda mixture thereof are most preferred. The epoxy resin preferably has anepoxy equivalent of 130 to 1,500 g/eq, more preferably 200 to 1,000g/eq.

No particular limitation is imposed on the species of the aforementionedamine compound (b), so long as the amine compound has two or moreprimary or secondary amino groups in a molecule thereof. Specificexamples include aliphatic primary amines such as ethylenediamine,polyethylenediamine, polyether-diamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, and xylylenediamine;alicyclic primary amines such as bis(aminomethyl)cyclohexane, andisophoronediamine; aromatic primary amines such as m-phenylenediamineand diaminodiphenylmethane; aliphatic secondary amines such as ethyleneoxide adducts of an amine such as ethylenediamine, polyethylenediamine,polyether-diamine, diethylenetriamine, triethylenetetramine,tetraethylenepentamine, or xylylenediamine; alicyclic secondary aminessuch as ethylene oxide adducts of an amine such asbis(aminomethyl)cyclohexane or isophoronediamine; piperazine; and dicyandiamide. Of these, polyethylenediamine, polyether-diamine,xylylenediamine, bis(aminomethyl)cyclohexane, and isophoronediamine aremost preferred.

The aforementioned water-absorbable resin preferably has a ratio ofepoxy resin (a) to amine compound (b) of 1:0.3 to 1:3, as represented byan equivalent ratio (epoxy equivalent:active hydrogen equivalent) ofepoxy group amount of epoxy resin (a):amount of hydrogen atoms directlybonded to amine nitrogen atoms of amine compound (b), more preferably1:0.6 to 1:2.5, particularly preferably 1:0.7 to 1:2.2.

When the aforementioned epoxy resin (a) and amine compound (b) aretreated at 0 to 150° C. for 1 to 48 hours, preferably at 40 to 120° C.for 2 to 10 hours, a hardened water-absorbable resin can be produced.

In the above hardening process, a generally known hardening acceleratormay be added in order to control hardening rate. Examples of suchhardening accelerators include tertiary amines, imidazoles, andderivatives thereof.

No particular limitation is imposed on the method for retaining anessential member of the present invention; i.e., hydroxylamine compoundor hydrazine compound, in water-absorbable resin. For example, thewater-absorbable resin is pulverized to an appropriate particle size,and the pulverized resin is immersed in an aqueous solution ofhydroxylamine compound or hydrazine compound at 5 to 100° C. for 0.5 to72 hours, whereby the compound can be retained in the water-absorbableresin.

The corrosion inhibitor of the present invention, formed of awater-absorbable resin in which an essential component; i.e., thehydroxylamine or hydrazine compound, has been retained, is employed as apackage product containing the essential component wrapped in a wrappingmaterial having gas permeability, which has an oxygen permeability of1,000 mL/m²·day·atm or higher at 25° C. and 60% RH. No particularlimitation is imposed on the type of gas-permeable wrapping material andthe structure of the package product. In one exemplary procedure, awater-absorbable resin which retains an essential component; i.e., ahydroxylamine or hydrazine compound, is charged into a gas-permeablewrapping material of laminated structure having a substrate made ofpaper, nonwoven fabric, perforated plastic film or sheet, etc., and theperiphery of the wrapping material is sealed by heat, to thereby producea package product containing the essential component wrapped in thewrapping material.

The corrosion inhibitor in the form of the above package product ishermetically placed in a gas-barrier container with a metallic object tobe stored. The gas-barrier container employed is a bag, a casing, a can,or a like container, which is made of a gas-barrier plastic or metallicmaterial. For example, the gas-barrier container may be a casing made ofa resin such as polyethylene, polypropylene, nylon, polyester, vinylchloride, or polystyrene, or a bag made of a laminate film or sheetmaterial formed of polyethylene, polypropylene, nylon, polyester, or asimilar polymer.

In the case where the gas-barrier material is plastic film or sheet, acoating such as aluminum, silicon oxide, or selenium oxide may bevapor-deposited on a surface of the film or sheet employed, in order toensure gas-barrier performance. Other than the aforementioned materials,metallic cans made of iron, aluminum, stainless steel, etc. may beemployed. The gas-barrier container preferably has an oxygenpermeability of 50 mL/m²·day·atm or less at 25° C. and 60% RH, and asteam permeability of 5 g/m² day or less at 40° C. and 90% RH, morepreferably an oxygen permeability of 10 mL/m²·day·atm or less at 25° C.and 60% RH, and a steam permeability of 1 g/m²·day or less at 40° C. and90% RH.

EXAMPLES

The present invention will next be described in detail by way of TheExamples and Comparative Examples, which should not be construed aslimiting the invention thereto.

Example 1

Polyethylene glycol diglycidyl ether (Denacol EX-841, product of NagaseChemicals Ltd., epoxy equivalent: 370 g/eq) (82 parts) and glycerolpolyglycidyl ether (Denacol EX-313, product of Nagase Chemicals Ltd.,epoxy equivalent: 141 g/eq) (2 parts) (epoxy equivalent:active hydrogenequivalent=1:2.0), which had been heated to 60° C. in advance, wereplaced in a 500-mL beaker. To the mixture, benzyldimethylamine (0.1parts) serving as a hardening accelerator was added, and the mixture wasstirred. To the mixture, m-xylenediamine (active hydrogen equivalent: 34g/eq) (16 parts) was added, and the mixture was stirred. The solutionmixture was poured into an aluminum mold and heated in a drier at 80° C.for one hour and further at 120° C. for one hour, to thereby produce ahardened resin product. The hardened resin product was pulverized bymeans of a mortar, and the pulverized product (3 g) was immersed in a 5wt. % aqueous hydroxylamine solution (100 mL) at 25° C. for 24 hours.Subsequently, the thus-water-absorbed hydroxylamine-containing hardenedresin product (percent water absorption: 300 wt. %, hydroxylaminecontent: 5 wt. %) was charged into a gas-permeable wrapping material(inside dimensions: 80 mm×50 mm, oxygen permeability 1,000mL/m²·day·atm) of laminate structure formed of paper/polyethylene film,and the periphery of the wrapping material was sealed by heat such thatthe resin was held by the polyethylene film, to thereby produce acorrosion inhibitor package product. The corrosion inhibitor packageproduct was subjected to the volatile corrosion inhibitor test(JIS-Z-1519). After completion of the test, the rust status of the testpieces was visually observed, and the status was evaluated on the basisof the following three ratings. The results are shown in Table 1.

A: No rusting

B: Rust observed on <50% surface of a test piece

C: Rust observed on ≧50% surface of a test piece

Example 2

The procedure of Example 1 was repeated, except that a 5 wt. % hydrazinewas used instead of a 5 wt. % hydroxylamine. The results of the volatilecorrosion inhibitor test are shown in Table 1.

Example 3

The procedure of Example 1 was repeated, except that a 5 wt. %N,N-diethylhydroxylamine was used instead of a 5 wt. % hydroxylamine.The results of the volatile corrosion inhibitor test are shown in Table1.

Example 4

The procedure of Example 1 was repeated, except that a 5 wt. %methylhydrazine was used instead of a 5 wt. % hydroxylamine. The resultsof the volatile corrosion inhibitor test are shown in Table 1.

Example 5

The procedure of Example 1 was repeated, except that a 5 wt. %ethylhydrazine was used instead of a 5 wt. % hydroxylamine. The resultsof the volatile corrosion inhibitor test are shown in Table 1.

Example 6

The procedure of Example 1 was repeated, except that a 5 wt. %1,1-dimethylhydrazine was used instead of a 5 wt. % hydroxylamine. Theresults of the volatile corrosion inhibitor test are shown in Table 1.

Example 7

The procedure of Example 1 was repeated, except that a 5 wt. %1,2-dimethylhydrazine was used instead of a 5 wt. % hydroxylamine. Theresults of the volatile corrosion inhibitor test are shown in Table 1.

Example 8

The procedure of Example 1 was repeated, except that polyethylene glycoldiglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.,epoxy equivalent: 551 g/eq) (91.5 parts) and m-xylenediamine (8.5 parts)(epoxy equivalent active hydrogen equivalent=1:1.76) were added insteadof polyethylene glycol diglycidyl ether (Denacol EX-841) (82 parts),glycerol polyglycidyl ether (2 parts), and m-xylenediamine (16 parts).The results of the volatile corrosion inhibitor test are shown in Table1.

Example 9

The procedure of Example 1 was repeated, except that polyethylene glycoldiglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.) (86parts), polypropylene glycol diglycidyl ether (Denacol EX-920, productof Nagase Chemicals Ltd., epoxy equivalent: 176 g/eq) (8 parts),benzyldimethylamine (1 part), and isophoronediamine (active hydrogenequivalent: 43 g/eq) (6 parts) (epoxy equivalent active hydrogenequivalent=1:1.77) were added instead of polyethylene glycol diglycidylether (Denacol EX-841) (82 parts), glycerol polyglycidyl ether (2parts), benzyldimethylamine (0.1 parts), and m-xylenediamine (16 parts).The results of the volatile corrosion inhibitor test are shown in Table1.

Example 10

The procedure of Example 1 was repeated, except that polyethylene glycoldiglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.)(86.6 parts), benzyldimethylamine (1 part), and1,3-bis(aminomethyl)cyclohexane (active hydrogen equivalent: 36 g/eq)(11.4 parts) (epoxy equivalent:active hydrogen equivalent=1:2.02) wereadded instead of polyethylene glycol diglycidyl ether (Denacol EX-841)(82 parts), glycerol polyglycidyl ether (2 parts), benzyldimethylamine(0.1 parts), and m-xylenediamine (16 parts). The results of the volatilecorrosion inhibitor test are shown in Table 1.

Example 11

The procedure of Example 1 was repeated, except that polyethylene glycoldiglycidyl ether (Denacol EX-861, product of Nagase Chemicals Ltd.)(88.3 parts) and triethylenetetramine (active hydrogen equivalent: 37g/eq) (11.7 parts) (epoxy equivalent:active hydrogen equivalent=1:2.02)were added instead of polyethylene glycol diglycidyl ether (DenacolEX-841) (82 parts), glycerol polyglycidyl ether (2 parts), andm-xylenediamine (16 parts). The results of the volatile corrosioninhibitor test are shown in Table 1.

Comparative Example 1

The procedure of Example 1 was repeated, except that pure water was usedinstead of an aqueous hydroxylamine. The results of the volatilecorrosion inhibitor test are shown in Table 1.

Comparative Example 2

The procedure of Example 1 was repeated, except that silica gel (5 g)was used instead of a water-absorbable resin. The results of thevolatile corrosion inhibitor test are shown in Table 1.

Comparative Example 3

The procedure of Example 1 was repeated, except that activated carbon (5g) was used instead of a water-absorbable resin. The results of thevolatile corrosion inhibitor test are shown in Table 1.

Example 12

Polyethylene glycol diglycidyl ether (Denacol EX-861, product of NagaseChemicals Ltd., epoxy equivalent: 551 g/eq) (88.3 parts) was placed in a500-mL beaker, and ion-exchange water (100 parts) was added, followed bystirring the mixture at 60° C. To the mixture, triethylenetetramine(active hydrogen equivalent: 37 g/eq) (11.7 parts) (epoxyequivalent:active hydrogen equivalent 1:1.97) was added, and the mixturewas further stirred. The resultant mixture was heated in a drier at 80°C. for two hours, to thereby produce a hardened resin product. Thehardened resin product was pulverized by means of a mortar, and thepulverized product (5 g) was immersed in an aqueous solution (100 mL) of1 wt. % 1,1-diethylhydrazine and 0.1 wt. % methylpentynol at 25° C. forfive hours. From the thus-immersed hardened resin product, and in amanner similar to that of Example 1, a corrosion inhibitor packageproduct was produced. The product was subjected to the volatilecorrosion inhibitor test. The results are shown in Table 1.

Example 13

The procedure of Example 12 was repeated, except that 0.1 wt. %methylbutynol was used instead of 0.1 wt. % methylpentynol. The resultsof the volatile corrosion inhibitor test are shown in Table 1.

Example 14

Polyethylene glycol diglycidyl ether (Denacol EX-861, product of NagaseChemicals Ltd., epoxy equivalent: 551 g/eq) (60 parts) was placed in a500-mL beaker, and benzyldimethylamine (0.2 parts) and ion-exchangewater (100 parts) were added, followed by stirring the mixture. To themixture, polyether-diamine (active hydrogen equivalent: 500 g/eq) (40parts) (epoxy equivalent:active hydrogen equivalent=1:0.73) was added,and the mixture was further stirred. The resultant mixture was heated ina drier at 80° C. for two hours and at 90° C. for three hours, tothereby produce a hardened resin product. The hardened resin product waspulverized by means of a mortar, and the pulverized product (5 g) wasimmersed in an aqueous solution (100 mL) of 1 wt. % 1,2-diethylhydrazineand 0.1 wt. % dimethylhexynol at 25° C. for five hours. From thethus-immersed hardened resin product, and in a manner similar to that ofExample 1, a corrosion inhibitor package product was produced. Theproduct was subjected to the volatile corrosion inhibitor test. Theresults are shown in Table 1.

Example 15

The procedure of Example 14 was repeated, except that wt. %1-ethynylcyclohexanol was used instead of 0.1 wt. % dimethylhexynol. Theresults of the volatile corrosion inhibitor test are shown in Table 1.

TABLE 1 Rust status Example 1 A Example 2 A Example 3 A Example 4 AExample 5 A Example 6 A Example 7 A Example 8 A Example 9 A Example 10 AExample 11 A Example 12 A Example 13 A Example 14 A Example 15 A Comp.Ex. 1 C Comp. Ex. 2 B Comp. Ex. 3 C

1. A corrosion inhibitor comprising a hydroxylamine compound representedby formula (1):

(wherein each of R¹, R², and R³ represents a hydrogen atom, a C1 to C6alkyl group, or a C2 to C4 alkenyl group, and each of these groups mayhave a substituent), or a hydrazine compound represented by formula (2):

(wherein each of R¹, R², R³, and R⁴ represents a hydrogen atom, a C1 toC6 alkyl group, or a C2 to C4 alkenyl group, and each of these groupsmay have a substituent) and a water-absorbable resin.
 2. The corrosioninhibitor as described in claim 1, wherein the compound represented byformula (1) is hydroxylamine or N,N-diethylhydroxylamine.
 3. Thecorrosion inhibitor as described in claim 1, wherein the compoundrepresented by formula (2) is at least one species selected from amonghydrazine, methylhydrazine, ethylhydrazine, 1,1- or1,2-dimethylhydrazine, and 1,1- or 1,2-diethylhydrazine.
 4. Thecorrosion inhibitor as described in claim 1, which further contains a C3to C10 acetylene alcohol.
 5. The corrosion inhibitor as described inclaim 4, wherein the acetylene alcohol is at least one species selectedfrom among 3-methyl-1-pentyn-3-ol, 3-methyl-1-butyn-3-ol,3,5-dimethyl-1-hexyn-3-ol, and 1-ethynylcyclohexanol.
 6. The corrosioninhibitor as described in claim 1, wherein the water-absorbable resin isa hardened resin obtained through reaction between a hydrophilic epoxyresin (a) having two or more epoxy groups in a molecule thereof and anamine compound (b) having two or more primary or secondary amine groupsin a molecule thereof.
 7. The corrosion inhibitor as described in claim6, wherein the epoxy resin (a) is at least one species selected from thegroup consisting of polyethylene glycol diglycidyl ether, polypropyleneglycol diglycidyl ether, glycerol polyglycidyl ether, and polyglycerolpolyglycidyl ether.
 8. The corrosion inhibitor as described in claim 6,wherein the amine compound (b) is at least one species selected from thegroup consisting of polyethylenediamine, polyether-diamine,xylylenediamine, bis(aminomethyl)cyclohexane, and isophoronediamine. 9.A package product comprising a corrosion inhibitor as recited in claim 1and a gas-permeable material which wraps the corrosion inhibitor.
 10. Amethod of inhibiting corrosion, comprising maintaining a metallic memberin a gas barrier container in the presence of the corrosion inhibitor asdescribed in claim
 1. 11. The corrosion inhibitor as described in claim2, wherein the compound represented by formula (2) is at least onespecies selected from among hydrazine, methylhydrazine, ethylhydrazine,1,1- or 1,2-dimethylhydrazine, and 1,1- or 1,2-diethylhydrazine.
 12. Thecorrosion inhibitor as described in claim 11, which further contains aC3 to C10 acetylene alcohol.
 13. The corrosion inhibitor as described inclaim 12, wherein the acetylene alcohol is at least one species selectedfrom among 3-methyl-1-pentyn-3-ol, 3-methyl-1-butyn-3-ol,3,5-dimethyl-1-hexyn-3-ol, and 1-ethynylcyclohexanol.
 14. The corrosioninhibitor as described in claim 7, wherein the amine compound (b) is atleast one species selected from the group consisting ofpolyethylenediamine, polyether-diamine, xylylenediamine,bis(aminomethyl)cyclohexane, and isophoronediamine.
 15. A packageproduct comprising a corrosion inhibitor as recited in claim 11 and agas-permeable material which wraps the corrosion inhibitor.
 16. Apackage product comprising a corrosion inhibitor as recited in claim 4and a gas-permeable material which wraps the corrosion inhibitor.
 17. Amethod of inhibiting corrosion, comprising maintaining a metallic memberin a gas barrier container in the presence of the corrosion inhibitor asdescribed in claim
 11. 18. A method of inhibiting corrosion, comprisingmaintaining a metallic member in a gas barrier container in the presenceof the corrosion inhibitor as described in claim 4.